The present invention is related to a semiconductor pressure sensor, and particularly, related to the technique for improving the environmental endurance of a semiconductor pressure sensor.
In the prior art technique, semiconductor pressure sensors are known which make use of a pressure detecting device formed on a silicon chip for measuring pressure. For example, a semiconductor pressure sensor is described in Japanese Patent Publication No. 2,637,633. This semiconductor pressure sensor includes a silicon chip provided on a glass support with a pressure detecting device.
However, this pressure sensor's structure provides the pressure detecting device on the silicon chip, to which the pressure medium to be measured is applied when a pressure medium to be detected is introduced to the surface where an electrical circuit is formed. Accordingly, if the pressure medium includes undesirable moisture or ions, fluctuation of an output level due to surface current leakage on the silicon chip will occur, thus preventing correct pressure signals.